The Claude NIST ECDSA seeds of the elliptic curves P-192 to P-521 had their origin revealed by an internal Anthropic model. In under half an hour, Claude discovered they came from the C library's lrand48 generator, initialized with Unix timestamps from 1997-1998, and not from hashes of secret phrases.
What happened?
The seeds of the P-192, P-224, P-256, P-384 and P-521 curves (adopted by NIST in 2000 in FIPS 186-2) were supplied by the NSA without explanation. This generated decades of speculation about possible backdoors. The most popular hypothesis, attributed to Jerry Solinas, was that they were hashes of a humorous phrase like “Give Bob and Jerry a raise”.
In October 2026, an Anthropic employee asked an internal Claude model to find the origin without mentioning that clue. The model identified the lrand48 pattern (which returns the top 31 bits of a 48-bit state), recovered the internal states with lattice basis reduction (LLL) and traced the srand48 initializations to timestamps between May 1997 and April 1998. For P-256, the published seed corresponds to the 1842nd candidate of a run started on August 16, 1997 at 01:52:34 UTC.
Why does this matter?
According to Anthropic, this is not a cryptographic break or a weakness in the curves. On the contrary, it makes intentional backdoors less plausible because the generation method is simple and reproducible. Filippo Valsorda's bounty was claimed and the $36,864 reward will be donated to the Internet Security Research Group (ISRG).
Claude also explained base points of some May 1997 curves (using FreeLIP), but some seeds (like B-163) and base points of other curves remain unexplained. Some viable candidates were skipped, but the team considers it unlikely that weakened curves were deliberately selected.
What changes in practice?
For most users and systems that use ECDSA (including HTTPS and digital signatures), nothing changes: the curves continue to be considered secure. The result increases confidence in the provenance of the parameters and demonstrates the ability of AI models to solve historical cryptographic problems quickly and verifiably. The code to reproduce the seeds was published by Anthropic.
Official source: Anthropic research.
Image credit: Anthropic — Source: Wikimedia Commons
By GeekikiBot
